Unsupported tenon areas

[LatakiaLover]

Meaning draft holes that overlap the mortise, especially at the "bowl end"...

Several of the tricky shapes people are making these days require such an overlap because drill bits are straight. But I don't recommend you do it unless you must. If it is optional, don't.

The reason being I've worked on several pipes lately where the combination of heat/humidity/tar absorption/expansion/etc. had caused the unsupported portion of the tenon to expand INTO the cavity enough to lock the stem in place. Tricky to remove, and the cause of a measurable percentage of snapped off tenons that are sent in for repair.

It also occurred to me that some smokers may be doing the "leave a cleaner in the pipe for a while after each smoke" thing, and using fluffy or tapered cleaners that are a tight fit. Outward pressure + hot stem material + repetition = shape change.

Probably some of all the above is responsible. Whatever the reason though, when it happens it's a mess, so best avoided in the first place.

Again, I'm not finger wagging, just supplying information for you designer guys to factor in when creating new shapes.

[LexKY_Pipe]

I thought I understood your comment until you said especially at the "bowl end" Not sure what you mean? But I have been known to be dense.

[LatakiaLover]

"Bowl end" meaning farthest from the button. The end of the tenon.

Sorry, this is one of those pictures are worth a thousand words situations. "Any place the tenon's outer surface ISN'T touching wood when it's installed in the pipe" is the hazard, and the closer to the tip/end of the tenon, the greater the risk it will flare/expand into the unsupported area. When it does, the stem is mechanically locked in place. Can't be either rotated or withdrawn.

Naturally, the thinner the wall of the tenon, the greater the risk.

[Tyler]

I guess I've never seen a pipe like this. I just can't picture what you're describing.

Tyler

[LexKY_Pipe]

No matter the shape, I attempt to not have the draft hole impact the rim of the mortise. The only shape that does that in my designs is an Oom Paul, and it does the overlap as you call it oh so slightly.

[JHowell]

Do you mean drilling through the mortise wall rather than drilling through the shank face? I would expect there to be very little moisture at the latter.

[Tyler]

Do you mean drilling through the mortise wall

Aha! Is that what we are talking about?

If so, I'm surprised that the diameter of the draught is big enough for the tenon to do much expanding into. I believe you, I'm just surprised.

[LatakiaLover]

Jack -- Yes. Much better way to phrase it. Thanks.

Tyler -- It's surprising, for sure. I've seen a number over the years, and two coming up in the same week made me think to mention it here. Most of the cases are older & smaller pipes with fairly thin tenon walls, but not all. One of the recent ones was a fairly new Stanwell of ODA size.

Never seen it with Lucite, only vulcanite, btw.

[JHowell]

Vulcanite is pretty compressible, and flows over time if subjected to constant pressure. I bought a beautiful vintage Robert clarinet mouthpiece (1940s) once on Ebay, but it had had a ligature tightened on it (ligature=hose clamp for reed) before it was put in the closet for decades. The rubber had flowed considerably, into sort of an hourglass shape. In what LatakiaLover describes, I can see the sharp edge of a draft hole that pierces the mortise wall pressing into the tenon and getting a bite over time.

[KurtHuhn]

I get it now. Kind of how antique glass windows "flow" and become thicker at the bottom. I've seen some very pronounced examples of this in years past.

[Nick]

wierd!